Firstly I would want them to fix the gear system. For a sequel, they could renew it entirely. There are two problems I see with this that need fixing.
1. You have to choose between style and abilities, as by no miracle the exact outfit you'd like to wear will have the abilities you need.
2. The rolling system leaves near impossible odds to get the gear abilities you want with given resources, pushing people to make use of save scumming and even hacking.
Personal sugestion from my side would be, since this is a sequel, separating gear and abilites entirely. Your clothes would have absolutely no influence on any of your abilities. Instead, they could use something like a bracelet system. There could three bracelets on the Inkling's arm that take the color of its ink. Top, middle, bottom replacing headgears, tops and shoes. Several for each brand with different abilities, just like it's currently done with the clothes. With this, they could take over the old system but leave style entirely up to the user's taste. Even systems like exclusive abilities (
) could be taken over. Instead of making
shirt exclusive, it's exclusive to the middle bracelet. Instead of making
shoes exclusive, it's exclusive to the bottom bracelet. Same goes for rarity of certain abilties. Like
is rare of headgears today, it could be rare for the top bracelet in the sequel.
With regard to the rolling system... I'd say it's about time to let us roll one slot at a time for a massively increased price. Quick reminder, currently we have the following odds for getting what we want in all three slots:
Natural Gear (Rolling the brand-favored ability in all three slots): 3% chance of succeeding for one roll. 95% of succeeding for 100 rolls.
Neutral Gear (Rolling neither brand-favored nor brand-unfavored abilities in all three slots): 0.02% chance of succeeding for one roll. 2% chance of succeeding for 100 rolls.
Unnatural Gear (Rolling brand-unfavored abilities in all three slots): 0.003% chance of succeeding for one roll. 0.3% chance of succeeding for 100 rolls).
That's... broken in my opinion, to say the least, and I absolutely understand everyone resorting to save scumming or other methods to bypass this system. And I'm sure Nintendo is aware of that too. So why keep this the way it is? Getting gear abilities in the honest way has nothing to do with skill, progress, or effort. It's luck. A damn high amount of luck. And that can be discouraging. I can't count how often I settled for less simply because I was afraid to lose what I had through a reroll.
Other than fixing the core of this game, I of course also want to see expanded gameplay. More modes, more stages and a lot more for the singleplayer mode. Maybe mixing online and singleplayer? I could imagine that to be fun. The ink mechanic has so much potential to deliver. Why limit this game to being a traditional shooter? I want modes that in fact don't have to do with splatting others in small stages with a way too simple objective. Thinking outside the box is what I want to see.